Determination Of Sound Transmission Class (STC) For Lecture Rooms In UTeM.

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DETERMINATION OF SOUND TRANSMISSION CLASS (STC) FOR UTEM LECTURE ROOM

ZAINORDIN ZHAFRAN BIN ZULKEFLI

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‘I / we admit that have read this work and in my / we opinion this work satisfied the scope and quality aspect for the

Bachelor of Mechanical Engineering (Automotive) awarded’

Signature :………

Supervisor Name 1 :………

Date :………

Signature :………

Supervisor Name 1 :………

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DETERMINATION OF SOUND TRANSMISSION CLASS (STC) FOR UTEM LECTURE ROOM

ZAINORDIN ZHAFRAN BIN ZULKEFLI

This Report is to fulfill course evaluation In

Bachelor of Mechanical Engineering (Automotive)

UNIVERSITI TEKNIKAL MALAYSIA MELAKA FACULTY OF MECHANICAL ENGINEERING

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CONFESSION

“I admit this report is my own work except for the summary and passage which each of it already been explained it source”

Signature :

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DEDICATION

Thanks to ALLAH S.W.T because with His blessings, I manage to finish this report according to the dateline.

I dedicate this report to

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ACKNOWLEDGEMENT

Alhamdulillah thanks to Allah, with His blessing I manage to complete this report in time.

I would like to thanks my supervisor Dr JANATUL ISLAH MOHAMMAD for her guidance and encouragement during completing this report.

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ABSTRAK

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ABSTRACT

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TABLE OF CONTENT

TITLE PAGE

CONFESSION ii

DEDICATION iii ACKNOWLEDGMENT iv ABSTRACT v

ABSTRAK vi

TABLE OF CONTENT vii

LIST OF FIGURE ix

LIST OF TABLE x

CHAPTER 1 INTRODUCTION 1.1 Background of The Project 1

1.2 Problem Statement 2

1.3 Objective 3 1.4 Scope 3

1.5 Project Planning 4

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CHAPTER 2 THEORY OF SOUND TRANSMISSION

2.1 Introduction 7 2.2 STC Rating 9 2.3 International Standard to Determine 12

Sound Transmission Classes (STC)

2.3.1 ASTM E413-73 Standard 12 2.3.2 ANSI/ASA S12.60–2002 Standard 13 2.4 Implication for School Design 15 2.4.1 Background Noise From External Sound Sources 15

2.4.2 Pass through Noise from Adjacent Spaces 15 2.4.3 Background Noise From Sources Within Room 17

2.5 Classroom size, proportion and sound absorption 18 2.6 Four Criteria Influence The Speech Intelligibility 20

2.7 Interior Noise Sources 23

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CHAPTER 3 RESEARCH METHODOLOGY

3.1 Introduction 30

3.2 Measurement Methodology 31

3.3 Equipment 38

3.3.1 RION sound level meter model NA 28 38

3.3.2 Thunder loudspeaker 39

3.3.3 Low cost curtain 40

CHAPTER 4 MEASUREMENT RESULT AND DISCUSSION 4.1 Introduction 41

4.2 Measurement Using Real Ongoing Lecture condition 42 4.3 Measurement No Ongoing lecture Condition 51

4.3 Measurement Using Curtain as acoustic Treatment 60

4.5 Discussion Of the Result 69

4.5.1Importance of the results obtained 71

4.6 Implication of the result 72

CHAPTER 5 CONCLUSIONS AND FURTHER WORK 5.1 Conclusions 73

5.2 Further work 74

REFERENCE 75

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LIST OF FIGURE

FIGURE PAGE

Figure 1: Sound /Surface Interaction: (a) Transmission, 8

(b) Absorption, (c) Reflection, (d) Diffusion Figure 2: Comparison of classroom acoustical environment 14

Figure 3: Sources of background noise in an unoccupied classroom 16

Figure 4: Reverberation 19

Figure 5(a): Noise Reduction between two spaces by a dividing wall 21

Figure 5(b): Noise Reduction between two spaces by a dividing wall 21

Figure 6: Signal-to-noise ratio (SNR) 22

Figure7: Figure 7.Gypsum Board Wall Construction 24

Figure 8: Door Layout Paths 26

Figure 9: Sound Travels over the partition wall 29

Figure 10: Block Diagram of Measuring Data when Classroom 4 is Empty 33

Figure 11: Measurement Location Map for condition i 34

Figure 12: Measurement Location Map for condition ii 35

Figure 13: Measurement Location Map for condition iii 36

Figure 14: This picture is taken in classroom 37

Figure 15: This picture is taken in classroom 37

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Figure 17: Thunder loudspeaker 39

Figure 18: Low cost curtain for acoustic treatment test 40

Figure 19: Graph point 1(ongoing lecture condition) 43

Figure 23: Graph comparison between 4 locations for ongoing lecture 50

Figure 24: Graph point 1 (Test) 52

Figure 28: Graph comparison between 4 locations for test condition 59

Figure 29: Graph point 1 (Treatment) 61

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LIST OF TABLE

TABLE PAGE

Table 1: STC Value for Walls 11

Table 2: Data sound level meter measurement for Lecture Situation point 1 42

Table 6: Data sound level meter Measurement No ongoing lecture point 1 51

Table 10: Data sound level meter measurement (Treatment) point 1 60

Table 14: The highest SPL data from sound level meter measurement at a 69

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LIST OF APPENDIX

NO TITLE PAGES

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CHAPTER 1

INTRODUCTION

1.1 Background of the Project

The amount of airborne sound blocked from transmitting through a partition is measured in a Sound Transmission Class (STC) rating. A higher STC rating will allow sound transmission through walls and increase the background noise level in the space, degrading the ability to hear and understanding speech [1].

The purpose of this classification is to provide a single-figure rating that can be used for comparing partitions for UTEM classroom. The rating is designed to correlate with subjective impressions of the sound insulation provided against the sounds of speech, sound receiver and sound sources in a classroom.

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2 1.2 Problem Statement

A sufficient level of acoustics quality in classroom or lecture room is important in order to provide effective learning and teaching environment. However if acoustic level in classroom does not meet the ANSI/ASAS12.60-2002 Classroom Acoustic Design Standard then this will disturb the speech intelligibility in classroom and reduce the interaction between teacher and students.

Some of the disadvantaged arise if the ANSI/ASAS12.60-2002 Classroom Acoustic Design Standard does is not met are as listed below:

a) Students do not understand what the teacher says and this will reduce the communication between students and teacher.

b) Students lose their focus in class and this will reduce the quality of studies and produce bad results during assessment.

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3 1.3 Objectives

The objective of this project is to carry out a measurement process in order to determine the sound transmission classes in a selected number of UTEM classrooms. Besides that, this project aims to evaluate some tests made to the existing classroom to improve the quality of learning and teaching in UTEM classrooms. If the standard is not met by existing classroom, some suggestions to improve the quality of learning and teaching in UTEM classrooms will be discussed as well.

1.4 Scope

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4 1.5 Project Planning

Gantt Chart PSM1

ACTIVITIES WEEK

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

TITLE CONFORMATION

OBJECTIVE & SCOPE

PROBLEMS STATEMENT LITERATURE REVIEW METHODOLOGY CONLUSION SUBMIT DRAFT REPORT

SUBMIT FULL REPORT

PRESENTATION

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5 Gantt chart PSM 2

ACTIVITIES WEEK

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

LITERATURE REVIEW MEASUREMENT RESULT ANALYSIS DISCUSSION CONLUSION SUBMIT DRAFT REPORT

SUBMIT FULL REPORT

PRESENTATION

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1.6 Report Structure

Chapter 1 presents the introduction of the project that will include the background, problem statement, scope and overall project.

Chapter 2 discusses about the previous studies on sound transmission classes, theory on sound transmission classes, international measurement standard for sound transmission classes and basic acoustic knowledge. This chapter also discusses the implication of school design, reverberation, evaluating speech intelligibility, sound reinforcement and noise criteria rating.

Chapter 3 discuss the project implementation of determine sound transmission classes, equipment in measurement, previous measurement method and chosen method of measurement for this project.

Chapter 4 presents the result and discussion of the measurement justifies the validity of the data taken.

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CHAPTER 2

THEORY OF SOUND TRANSMISSION

2.1 Introduction

Intensity is a physical measurement of a sound wave that relates to how loud a sound is perceived to be. We can also measure the frequency of a sound wave, which we perceive as pitch. For example, on a piano, the keys to the right have a higher pitch than those to the left. If a sound has just one frequency, it is called a pure tone, but most everyday sounds like speech, music, and noise are complex sounds composed of a mix of different frequencies. The importance of frequency arises when a sound wave encounters a surface: the sound will react differently at different frequencies. The sensitivity of the human ear also varies with frequency, and we are more likely to be disturbed by medium-to high-frequency noises, especially pure tones [2].

Think of sound as a beam, like a ray of light, passing through space and encountering objects as shown in figure 2. When sound strikes a surface, a number of things can happen, including:

Transmission-- The sound passes through the surface into the space beyond it, like light passing through a window.

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Figure 1: Sound /Surface Interaction: (a) Transmission, (b) Absorption, (c) Reflection, (d) Diffusion

(Source: University of Kansas Architectural Engineering faculty 1998)

Reflection-- The sound strikes the surface and changes direction like a ball bouncing off a wall.

Diffusion-- The sound strikes the surface and is scattered in many directions, like pins being hit by a bowling ball.

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9 2.2STC RATING

Many educators feel it is important to improve acoustics in classrooms used by students because less than acoustically optimal conditions in the classroom affect the academic performance of all students. Many experts believe that students miss up to 33 percent of the oral communication that occurs in the classroom and this will reduce the quality of learning [3]. Because of that many educator and experts in universities have has done a research to find the best solution to this problem.